Safety door lock



Feb. 19, 1952 E. c. LARSON SAFETY DOOR LOCK Filed June 15, 1948 Patented Feb. 19, 1952 SAFETY DOORLOCK Erling C. Larson, Bellevue, Wash., assignor to National Products Company, Seattle, Wash., a corporation of Washington ApplicationJune 15, 1948,. Serial No. 33,142

8 Claims. 1

- This invention relates to safety door-locks. and

particularly a safety lock for use on four-door automotive. vehicles. The purpose of the invention is to provide'a. device which will. permit the rear door tobe opened. only by first opening the front door, thus to provide a device which. will secure the rear door in closed position while the car is in motion and thereby give positive assurance that a child occupying, the rear compartment will not, by pulling, on a rear door handle, cause the. latter to open and either fall or bepulled by force of. suction through the open door.

As. further and particular objects the invention aims to provide a safety lock for this purpose which may be inexpensively constructed, one which may be. quickly and easily installed and Which will be entirely concealed from view when the doors of the vehicle are. closed, which will give a positive locking action, and. which, however, will enable the rear door to remain open while the front door is closed and yet permit such rear door to be then freely closed without first opening the previously closed front door.

Having'the above and still additional objects and advantages in view which will appear ahd be understood in the course of the following description and claims, the invention consists in thenovel construction and in the adaptation and combination of parts hereinafter described and claimed.

In the accompanying drawing: 7

Figure 1 is a horizontal sectionl view portraying, fragmentarily, the front and rear doors together with the dividing post of a four-door vehicle body and showing the now preferred embodiment of the present invention. in its operating association therewith, full? and dotted lines being employed to indicate the front door inboth open and closed positions;

Fig; 2 is a vertical sectional view thereot taken to an enlarged scale the longitudinal median line of the safety-lock, the front door being here shown in. closed position,

Figs. 3 and 4 are front and rear elevational views, respectively, of the door-lock and incorporating; in each instance, a fragmentary showing of the dividing post; and

Fig. 5 is a fragmentary transverse vertical sectional view on line 5-5 of Fig. 2.

Referring to said drawing, the numeral 5 desighates the dividing post. of a four-door vehicle body, and 6 and 1 the front door and the rear door, respectively, and which are eachindicated as being hinged along the end edge-remotefrom the post. While the doors are presumed to carry the usual or suitable means which interact with complementing. means provided upon the post for releasably locking the doors in their closed position, the operation of the present safety-lock is entirely independent of the operation of these ordinary door-locking instrumentalities and I have therefore deleted from the drawing any illustration of the latter.

According. to the present invention, and having reference to the illustrated. preferred embodiment, there is provided a tubular casing open at both ends and so mortised into the dividing post as to have one of said end openings exposed to the frontface and the other end opening exposed to the back face of the post,. the casing being :omposed of two telescopically associated parts to admit of the same being contracted or expended in adapting the same to various widths of posts to. which the device may be applied.

- The casing member which opens to the front face sirablyof a square shape.

of the post, and. which I designate I0, is made secure to the post by counter-sunk screws H which are received through wing-flanges l2 and I3, and the other casing member, designated M, has a. reduced terminal neck which fits in a hole of corresponding size drilled through the back Wall of the post. A thread connection between the two casing members gives the necessary endwise adjustment to cause the shoulder which is defined by such neck to be brought firmly to bear against the inner face of said wall.

The casing member H! has its threads cut internally, and these threads extend. forwardly for only a portion of the length of the member whereat. there occurs a smooth bore 15 which is interrupted at the end extremity of the member by an inwardly directed annular lip IS. A piston H is received for endwise sliding movement in this bore, and presented by the piston is a reduced axial prolongation. which fits the inner perimeter of the lip and projects forwardly beyond the frontal face of the casing, this prolongation terminating in a tapering nose l8. The piston has a through center-bore and is also counter bored, as at 20, from the frontal end, and there is provided, extending inwardly from the counter-bore, a co-axial and relatively deep socket 2|: which, sectional-1y considered, is de- Accommodated by the socket is the squared head 22 of a draw-bar 2t. and. such draw-bar extends rearwardly from the piston presents a threaded end which screws.- into a locks-bolt 24', the lock -bolt being j oumale'd for: sliding movement within a centerspring,,denoted 28, likewise bears upon the piston but exerts its thrust force therefrom to the lockbolt, consequently projecting the lock-bolt directively from the piston but within a travel limit prescribed by the permitted movement of the draw-bar. For the purpose of localizing the lockbolt and the piston against liability of relative rotary movement, the two ends of the last-men- .tioned spring are directed parallel to the axis and find engagement in mating sockets provided by the lock-bolt and by the piston.

As the complements of the taper-nosed piston and the lock-bolt, there are screwed or otherwise firmly secured upon the end faces of the vehicle doors '6 and I a respective strike-plate, as an and 3|, placed to extend transverse to the end face and in each instance providing an inwardly rolled lead-in shoe, as 32 and 33, located upon the inner side of the door. The strike-plate 3D, and namely the plate for the front door 6, is

an imperforate plate whereas the plate 3| presents a bolt-hole 34 which, with an underlying hole 35 drilled in the end wall of the rear door I, is

adapted upon a closing of the door to be brought into mating registration with the lock-bolt. The bolt openings 34 and 35 are preferably given a diameter somewhat greater than the diameter of the bolt, thus to give the bolt free access to the openings. Also, when the bolt is shot and the vehicle is in motion, the fact of these holes being oversize eliminates possibility of chatter and yet accomplishes the intendedand necessary end of positively preventing the back door from being opened.

. The operation of my safety-lock device is believed ,to be clear. The piston acts as a push button and, when the front door 6 is opened, the spring 21 exerts its thrust to press this push-but 4 quence, substantially proof against liability of damage in that either door may be closed while the other door is open or closed, but at the same time precluding the back door from being opened excepting by first opening the front door.

In order to adjust the throw of the bolt, it

- is onlynecessary to exert thumb-pressure upon may be made in the details of construction withton outwardly into the exposed position in which it is shown in Fig. l, and the lock-bolt 24 is responsively retracted in that the head 22 of the draw-bar 23, bottoming against the floor of the socket 2|, then ties the lock-bolt directly to the push-button as a trailing appendix thereof. Having drawn the bolt, the rear door may perforce be opened by operation of the ordinary handle controls provided for this purpose. As the front door is now closed, and which operation may be performed whether the rear door has been first closed or remains in an open position, the strike plate 3| forces the nose of the push-button inwardly and the lock-bolt moves in concert therewith due to the action of the spring 28 in yieldingly influencing the bolt directively therefrom. Should this action take place while the rear door occupies an open position the rear door may be thereafter freely closed in that the contact of the lead-in shoe 33 with the tapering end of the bolt presses the bolt inwardly counter to the yielding thrust of the spring, the head of the draw-bar being simply backed up in its socket 2| until the doors closing movement brings the holes 34-45 into registration with the bolt whereupon the bolt is shot home by the suppressed load of the spring 28. My safety lock is, in consethe exposed end of the bolt and force the same inwardly in a degree sufiicient to cause the head 22 to clear the socket 2|, whereupon a screwdriver may be applied to the cross-slot 36 of the exposed head and the draw-bar screwed to either a greater or lesser extent into the bolt to modify the spacing between the bolt and said head 22. The-depth of the socket 2| is perforce such as will preclude the head from being backed out of the" socket by normal operating movements of the bolt. 7

While I have illustrated and described my nowpreferred embodiment, it is apparent that changes outrdeparting from the spirit of the invention. In this connection it should, perhaps, be here pointed out that the invention is in no sense limited to that type of, four-door vehicle ,body in 'which the doors both close against the dividing post. It is entirely feasible to insert and slidably mount, within a door hinged to the post 5, a rod of such length as to extend from one to the other endedge of the door, and cause the outer end of this rod to serve as the locking bolt while thrust-actuating the inner end from a functioning counterpart of the bolt 24. Also, the lockboltcould be manually controlled from a remote point by means of a wire housed in a flexible conduit, in which event the wire would desirably run downwardly through the post and lead under the floor of the front compartment to the instrubodies of the character having a dividing post "exposing the nose of the push-button beyond the front face of the post, the nose of said'push-bu'tton being formed with an axial socket dimensionally larger than the bore, a bolt mounted in the rear partof said casing for 'endwise sliding movement into and out of a position exposing an end thereof beyond the rear face of the post, a spring acting upon the push button to urge the same forwardly, a second spring exerting its thrust from the push-button to the bolt for urging'the latter rearwardly, and a headed draw-bar slidably'received throughithe bore of said pushbutton with its headed end bearing against the floor of the socket and; connecting by-its other end with the bolt.

2. In a safety door-lock for four-door vehicle bodies of the character having a dividing post between the front and rear doors, the combination of a cylindrical casing open at both ends and mortised into the post to have its front end exposed to the front face and its back end exposed to the rear face of the post, a push-button provided with a through center-bore and mounted in the forward part of said casing for endwise sliding movement into and out of a position exposing the nose of the push-button beyond the front face of the post, the nose of said pushbutton being formed with an axial socket dimensionally larger than the bore, a bolt mounted in the rear part of said casing for endwise sliding movement into and out of a position exposing an end thereof beyond the back face of the post, a spring acting upon the push-button to urge the same forwardly, a second spring exerting its thrust from the push-button to the bolt for urging the latter rearwardly, and a headed draw-bar slidably received through the bore of said pushbutton with its headed end bearing against the floor of the socket and having the rear end adjustably threaded in the bolt.

3. The structure of claim 2 providing means normally holding the bolt and the draw-bar against relative rotary movement in order to maintain the adjustment given to the draw-bar.

4. Structure according to claim 3 in which the head of the draw-bar is non-circular and with the axial socket being sectionally of a corresponding shape.

5. In a safety door-lock for four-door vehicle bodies of the character having a dividing post between the front and rear doors, the combination of a casing open at both ends and mortised into the post to have its front end exposed to the front face and its back end exposed to the rear face of the post, a push-button mounted in the forward part of said casing for endwise sliding movement into and out of a position exposing the nose of the push-button beyond the front face of the post and formed to provide, open to the nose end and located axially thereof, a bore urge the same forwardly, a second spring exerting its thrust from the push-button to the bolt for urging the latter rearwardly, and a headed draw-bar slidably received through the smaller bore of said push-button with its headed end bearing against the floor of the socket and having the rear end adjustably threaded in the bolt, the head of said draw-bar having a non-circular shape closely fitting the socket, and said socket having a depth exceeding the stroke travel of the bolt.

6. The structure of claim 5 providing means normally holding the bolt and the draw-bar against relative rotary movement in order to maintain the adjustment given to the draw-bar.

'7. In a safety door-lock for a vehicle body of the character providing front and rear passenger compartments with a. door to each said compartment and with the door openings being separated by a hollow dividing post, a housing structure comprising an open-ended tubular casing formed to provide a flange at one end and having the other end necked down providing a reduced terminal neck, said flange being pierced with screw holes and said terminal neck having a length approximating the thickness of the wall of the post, the post providing co-axial openings in its front and rear Walls one of which accommodates the body proper of the casing and the other of which provides a mating fit for the terminal neck, the flange being screwed tight against the outer face of one side of the post to bring the shoulder defined by said terminal neck snugly to bear against the inner face of the other side of the post.

8. Structure according to claim 7 in which the tubular casing is comprised of two telescopically associated parts threadedly interconnected to accommodate the casing to posts of different widths.

ERLING C. LARSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,790,104 Levitt et al. Jan. 27, 1931 2,161,930 Niswonger et a1. June 13, 1939 FOREIGN PATENTS Number Country Date 522,381 Great Britain June 17, 1940 

